public class CargoBoat {
   int realContent;
   int maxContent;
   public void setMaxContent(int c) {
     maxContent=c;
   }
   public void loading(int m) throws DangerException {
     realContent += m;
     if(realContent>maxContent) {
        realContent-=m;
        throw new DangerException();
    }
    System.out.println("目前装载了"+realContent+"吨货物");
   }
}
